1. Field of the Invention
The present invention relates to mud flaps for trucks and other transport vehicles. More specifically, the present invention relates to an automatically lifting mud flap assembly.
2. The Prior Art
One of the areas which is highly regulated, and one which can cause a great deal of expense to comply with, is the generally mandatory use of truck wheel or mud flaps. It cannot be denied that mud flaps are required to protect other vehicles and pedestrians. Conventionally, mud flaps are suspended from the truck body rearwardly of the rear truck wheels to prevent mud, stones or other debris material from being thrown or rearwardly ejected from the truck wheels and striking trailing motor vehicles or people. Generally, the mud flaps are merely suspended freely and therefore when the truck is traveling in loose ground or gravel in reverse, the flaps are often torn by coming in contact with the rear tires.
Large truck such as dump trucks used in interstate commerce are required by law to be provided with mud flaps behind each set of rear wheels. Such flaps are required to protect other vehicles and persons from rocks and other debris being rearwardly ejected from the truck wheels. Such flaps often can be torn from the rear of the vehicle when it is backed into some objects or in the case of a dump truck, when the flap is buried by the load being deposited from the dump truck. The resultant lack of a proper mud flap on many vehicles, thus, gives rise to injuries and property damage.
A serious difficulty arises when the required flaps are incorporated behind the rear wheels of dump trucks having tiltable dump beds. Flaps normally mounted on dump trucks are rigidly secured to the truck frame. As a truck discharges its load of sand, gravel or related material, a large pile of the dumped material forms beneath the rear of the vehicle. The material surrounds the flaps on all sides and effectively secures the flaps to the pile. Most flaps are fabricated from a resilient material which can be repeatedly folded or bent, because the flaps are buried in the dumped material. Often great forces are applied to the flaps and their mounting brackets as the forward movement of the truck pulls the flaps from the grip of the dumped material. Over a period of time, the flaps become damaged and rips develop in the flaps or the flaps are ripped from the brackets. The cost to replace the flaps is substantial. Also, there are fines for driving without flaps or with damaged flaps.
The prior art contains various solutions to the problem of damaged flaps. U.S. Pat. No. 2,981,553 to Zerbe, Sr. is an automatic flap system for moving the flaps behind the rear wheels. The patent describes a system which moves the flaps out of the way when the truck is put in reverse gear. The system uses one pulley connected to a single long cable. The long cable connects at the rear of the truck to two shorter cables. These two shorter cables connect to each of the mud flaps. When power is provided, a motor rotates the pulley which in turn pulls the long cable. This cable, elaborately connected to the shorter cables, pulls the flaps up. A pivot point serves as an axis to permit the flaps to pivot upwardly and out of the way. The problem with this system is that it is spread out over the transmission of the truck. It is difficult to install and the long single cable is easily damaged, because of its exposure to the elements. The smaller cables tend to weaken with the tension applied from the larger cable. Additionally, the control box contains an elaborate system of solenoid coils, switches and armature. Another problem is that this is a single system which operates both flaps. Therefore, if the system malfunctions, both flaps are out of service.
In U.S. Pat. No. 3,203,710 to Harting, Jr. and U.S. Pat. No. 3,806,196 to Cole et al, a mud flap retractor is described for a dump truck. The retractor is a mechanical cable system which is bolted to the truck. The cable runs to the body through a front guide and there to the mud flap. When the truck dumps its load, the raising of the body raises the mud flaps. The flaps curl inward and out of the way of the load being dumped. The Harting, Jr. patent has to have specially designed mud flaps, and the Cole et al patent adds a long heavy pipe which is fixedly connected to both flaps. A common problem with these type of retractors is that the mud flaps are in the down position when the truck is traveling in reverse. Thus, the wheels can catch the mud flaps and still cause tearing or ripping.
U.S. Pat. No. 3,582,109 to Moore is a mud flap retraction apparatus. Metal strips are affixed to the bottom of the mud flaps to protect the bottom of the flaps. These metal strips also secure a cable in the center of each strip. The cable extends upwardly along the outside surface of the mud flap and through an aperture in the bed of the truck body. A metal conduit receives each cable and converges into a V-shaped structure wherein the two cables connect to a single cable. The common cable connects to a lever arm and piston.
The lever arm is pivotally secured at one end and coupled to a rod of the piston in the center thereto. A solenoid valve switching circuit controls an air storage tank and compressor to pump air into a cylinder which in turn pushes the piston out. When the piston extends out of the cylinder, the lever arm is pushed towards the rear of the truck. This releases the flaps simultaneously and the flaps fall into the down position. To retract the flaps, the switching circuit is activated which results in the air being removed from the cylinder. This in turn allows the piston to be disposed in the cylinder. The movement of the piston forces the lever arm to move toward the front of the truck. The lever arm pulls on the cable which simultaneously pulls on each of the cables attached to the respective flap. The flaps begin to retract and are fully retracted when the piston rests in the cylinder. The system of this patent is a single system which has to be mounted to the body of the truck. With only one air cylinder and piston controlling both flaps. the system is prone to malfunctioning.
U.S. Pat. No. 4,097,090 to Payne et al discloses another flap retraction system. The system is attached to the dump box of the truck rather than to the body. More specifically, the system is attached to the tailgate of the dump box. Each flap is sandwiched between a pair of rectangular shaped metal plates. Additionally, each flap is attached to a separate bracket and piston system. The retraction of the flaps only occurs when the dump box is dumping. Here, the specially designed flaps are expensive and cumbersome, and the system is complex and difficult to install.
In U.S. Pat. No. 5,582,431 to Anderson, still another retractable mud flap assembly for a motor vehicle is described. The assembly includes an enclosure to receive the flap and a downwardly curved lip for guiding the flap into the assembly. A scrapper is attached near the lip to scrap the wheel side of the flap when retracted, in an attempt to remove debris such as mud and rocks which will clog and damage the assembly. A linear actuator is provided for each flap to retract and extend the respective flap based on a control lever mounted in the cab. The linear actuator can also be configured to retract the flaps whenever the vehicle is placed in reverse. While the assembly eliminates the springs and cables of other prior art systems, it still must utilize special mud flaps and complex mounting procedures under the cargo box of the truck. Thus, the assembly is expensive and difficult to install.
In order to overcome the problems and disadvantages of the prior art mud flap retraction assemblies, the present invention takes advantage of the standardization of the size and shape of mud flaps according to the regulations of the U.S. Department of Transportation. The present invention provides a dual automatic mud flap lifting assembly which mounts separately adjacent each set of rear wheels. The assembly is easy to install and is simple in operation. The operator removes each existing mud flap and mounts an elongated control housing in the existing area of the removed flap. The flap is then reattached along the bottom of the installed housing. A metal lifting bar is attached to the lower end of each flap and a cable extending from the housing is securely attached to an eye hook or other mounting element of the lifting bar.
More specifically, the elongated mounting box is in the shape of a long rectangular box which has upper and lower mounting edge plates that extend from the top and bottom at the back of the housing or box. Both mounting edge plates have holes spaced longitudinally therealong which match the standard size and spacing for the mounting holes of the mud flaps. Hence, the elongated control housing can be mounted directly on the truck body by the upper mounting edge plate at the location where the mud flap has been removed. The mud flap can then be reattached onto the elongated control housing along the lower mounting edge plate.
The cable which raises and releases the mud flap is actuated preferably by a simple air cylinder and cable pulley assembly housed inside the elongated mounting box or housing. Appropriate air lines connect the air cylinder through a conventional electric air valve to the pneumatic system typically installed on the truck or transport vehicle, and an electric control at the vehicle dashboard is electrically connected to the air valve for manually actuating the cylinder to an extended or retracted position. When the air cylinder is actuated to extend the actuating rod, the cable pulley system causes the cable to retract into the mounting box thus automatically raising the mud flap. When the air cylinder is actuated to retract the actuating rod, the cable pulley system allows the cable to be played out of the mounting box thus permitting the mud flap to extend downward to its normal extended position. In addition, the electric air valve is preferably wired to the back up lights at the rear of the vehicle so that the air cylinder is automatically actuated to raise the mud flaps when the vehicle transmission is put into reverse.
In accordance with the foregoing, it is an object of the present invention to provide at least two control boxes, each box being detachably mounted on the rear portion of a motor vehicle for separately raising and lowering the mud flaps.
It is a further object of the present invention to provide each control box with a top edge having standardized means for attaching the control box to the rear portion of the motor vehicle, and a bottom edge having standardized means for reattaching the mud flap to the bottom edge of the control box.
Another object of the present invention is to provide an air cylinder and cable pulley system mounted inside the control box for raising and lowering the bottom edge of the mud flap.
A further object of the present invention also is to provide a T-arm rigidly mounted to the outer end of the air cylinder which has at least two pulleys of the pulley system rotatably mounted thereon with a third pulley rotatably connected to the box at a predetermined location which plays out and reels in the cable during alternate reciprocation of the air cylinder actuating arm.
Still a further object of the present invention is to provide an electric air valve connected to the air cylinder for supplying air to the air cylinder from the standard pneumatic system of the truck or other vehicle.
Yet another object of the present invention is to provide a control system electrically connected to the electric air valve and back up lights of the motor vehicle, with a switch electrically connected to the control system for manually switching the control system; and means for illuminating in the vehicle control panel the position of the mud flap.
Yet still another object of the present invention is to provide an automatic lifting mud flap assembly in accordance with the preceding objects and which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible, long lasting and relatively trouble free in operation.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.